diff --git a/pkgs/development/compilers/gambit/unstable.nix b/pkgs/development/compilers/gambit/unstable.nix
index 41d0ee930bf..067a409ac1c 100644
--- a/pkgs/development/compilers/gambit/unstable.nix
+++ b/pkgs/development/compilers/gambit/unstable.nix
@@ -1,12 +1,12 @@
 { stdenv, callPackage, fetchgit }:
 
 callPackage ./build.nix {
-  version = "unstable-2018-08-06";
-# git-version = "4.8.9-77-g91a4ad2c";
+  version = "unstable-2018-09-03";
+# git-version = "4.9.0";
   SRC = fetchgit {
     url = "https://github.com/feeley/gambit.git";
-    rev = "91a4ad2c28375f067adedcaa61f9d66a4b536f4f";
-    sha256 = "0px1ipvhh0hz8n38h6jv4y1nn163j8llvcy4l7p3hkdns5czwy1p";
+    rev = "7cdc7e7b9194b2c088c0667efaf7686a4ffd0d8a";
+    sha256 = "06mmi8jkinihfirz4gjfw2lhxhskiqf3d47sihzx10r60asyqcxg";
   };
   inherit stdenv;
 }